Tuesday, November 19, 2013

Appalachian Cave Harvestman
Tolus appalachiusGoodnight and Goodnight, 1942Conservation status: IUCN Red List - Not Assessed; NatureServe - G3G4 (Alabama: SNR; Tennessee: S3). This species is tracked by the state of Tennessee.Description:Tolus appalachius is one of three described species of troglobiotic harvestmen in the Interior Plateau. Harvestmen are arachnid cousins of spiders but they lack silk organs and venom glands in their chelicerae (mouthparts). In addition, the cephalothorax and abdomen are fused in harvestmen but are distinct in spiders. Tolus appalachius is a small cave-dwelling relative of the "daddy longlegs" you might find in your basement or shed. It lacks eyes, is depigmented and has exceptionally long legs relative to the size of the body. The body is oval in shape and 2-4 mm long in adults, with legs up to 20 mm in length. The legs and chelicerae appear white in color, while the body is often a light creamy orange-white. The body of younger instars appears completely white.Distribution: This harvestman occurs in caves primarily along the Western Escarpment of the Cumberland Plateau from southern Fentress and Overton counties, Tennessee, south-southwestward into Jackson County, Alabama. Tolus has been reported from about 20 caves but likely occurs in many other cave systems.Habitat:Tolus is primarily reported from the dark zone of caves where it often found in moist microhabitats, such as on or underneath decaying wood, rocks along the stream margins or within crevices in cave walls, particularly near the junction of mud banks and solid rock. It is seldom found in drier cave passages.

Adult from Grundy Co., TN (Photo by Matthew L. Niemiller)

Natural History: Very little is known about the natural history of cave-dwelling harvestmen, including T. appalachius. Presumably, this species has an omnivorous diet like other harvestmen, feeding on smaller invertebrates and scavenging on fungi, decaying vegetation and animal matter. Nothing is known regarding reproduction in this species. Small instars have been found throughout the year, suggesting that reproduction may be not be seasonal. Like other harvestmen, Tolus clean their legs after feeding by running each leg through their chelicerae. When disturbed, Tolus will often play dead tucking their long legs into their body. Unlike several species of surface-dwelling harvestmen, cave-dwelling T. appalachius are not known to aggregate in large numbers of individuals.Conservation: Most populations are reportedly small based on collection data. I have seen as many as 18 individuals during a cave bioinventory. This species is assigned a global NatureServe conservation rank of 'Vulnerable' to 'Apparently Secure' (G3G4), but it has not yet been assessed under IUCN Red List criteria. Like other cave terrestrial invertebrates, Tolus populations may be threatened by habitat degradation, pollution, flooding associated with impoundments and significant human visitation. No species-specific management or conservation plans are being conducted at this time. Entrances to almost all known cave localities are owned by private landowners.Notes: A population in Overton County, Tennessee, may be distinct and warrant recognition as a new species. Hedin and Thomas (2010) recently investigated convergent morphological evolution in cave harvestmen, including Tolus appalachius.Select ReferencesGoodnight CJ, Goodnight ML. 1942. New Phalangodidae (Phalangida) from the United States. American Museum Novitates 1188: 1-18.Goodnight CJ, Goodnight ML. 1960.
Speciation among cave opilionids of the United States. American Midland
Naturalist 64: 34-38.

Monday, August 26, 2013

East Tennessee Cave BeetlePseudanophthalmus tennesseensisConservation status: IUCN
Red List - Not Assessed; NatureServe - G3 (Tennessee: S2).
This species is tracked by the state of Tennessee.Description:Pseudanophthalmus tennesseensis
is a small, eyeless and depigmented ground beetle red to reddish-brown in coloration. Adults are only 4 mm in length and lack wings. They have prominent, long legs and thread-like antennae. Like most Pseudanophthalmus, this species is pubescent, possessing three well-defined pairs of discal setae (chitinous hairs) on the elytra, a character used to separate the genus from other co-occurring genera of cave carabid beetles. Species identification is difficult in this genus and requires the dissection and microscopic examination of male genitalia. This species is the type species of the P. tennesseensis species group found in east Tennessee.

Distribution:Pseudanophthalmus tennesseensis is
known from only four cave systems in the Ridge and Valley of east Tennessee: three caves in Knox County and one cave in Roane County. All of these cave systems lie south of the Copper Creek Fault in Knox and Roane counties. A potential new population was discovered in Knox County in the Keller Bend area of the Tennessee River to the southeast of all known localities, but taxonomic identification has not yet been confirmed.

Habitat: Most specimens of P. tennesseensis have been collected primarily under rocks or rotting wood found on damp silt away from streams. However, the lone specimen found in the potential new locality in Knox County, Tennessee, was found near a rimstone pool.

Natural History: Little information is available regarding the life history and ecology of P. tennesseensis. Larvae have not been reported. Based on information from studies of other Pseudanophthlamus species, eggs of this species are probably laid in autumn with larvae appearing in winter. Larvae then pupate in late winter into early spring with tenerals (soft-bodied adults shortly after emerging from pupae or from molting) appearing the following summer in June and July. By the following autumn, beetles are almost fully sclerotized. Pseudanophthalmus beetles are predatory and are often actively observed walking along cave mud and sediments along streams and other sources of water. The diet of P. tennesseensis has not been studied but likely includes enchytraid and tubificid worms found in association with cave mud and sediments. Predators are unknown. This species is not known to co-occur with any other cave carabid beetles. Data on population size is unavailable. Valentine (1937) collected a male and female on separate trips from the type locality, Cherokee Caverns (TKN22) in Knox County, while Barr (1965) collected five topotypes from the same cave in 1958. Barr (1965) also reported that the species was "comparatively abundant" from a cave in Roane County, Tennessee. A recent bioinventory of this cave found only two P. tennesseensis in May 2013. Conservation: Pseudanophthalmus tennesseensis is known from just four localities in a relatively small geographic area. Most populations are reportedly small in size based on collection information. Accordingly, the species is assigned a global NatureServe conservation rank of 'Vulnerable' (G2) but has not yet been assessed under IUCN Red List criteria. Cave beetle populations may be threatened by habitat degradation, pollution, flooding associated with impoundments, and human visitation. At least two localities currently or have received considerable human visitation. With increased human presence in caves comes increased risk to beetle populations because of vandalism, littering, disruption of cave microhabitats, and potential trampling. However, no data exist linking any of these threats with possible population declines. No species-specific management or conservation plans are being conducted for P. tennesseensis at this time. Entrances to all known cave localities are owned by private landowners. The type locality was formerly a small, commercial cave but operations have since ceased. A potential new locality was discovered during a biological inventory of caves in Knox County in May 2013.

Monday, February 18, 2013

Alabama CavefishSpeoplatyrhinus poulsoniConservation status: IUCN Red List - Critically Endangered C2b; NatureServe - G1 (Alabama: S1). Listed as Endangered under the U.S. Endangered Species Act. Listed as Endangered in Alabama.Description:Speoplatyrhinus poulsoni is an eyeless and depigmented amblyopsid cavefish that is pinkish-white in color with some structures, like fins, fin rays and the venter, that are quite translucent. Morphologically, it is the most cave-adapted fish in the family Amblyopsidae. Adults are typically 30-58 mm (1.2-2.3 inches) standard length (SL). Both adults and juveniles have an extremely elongate and flattened snout with a terminal mouth that is duck-like in appearance. Unlike other amblyopsid cavefishes, S. poulsoni lacks branched fin rays, and the fin membranes are incised giving a spiked appearance. Pelvic fins are lacking. Fin rays counts are as follows: 9 (9-10) dorsal, 8 (8-9) anal, 9 (9-11) pectoral, and 22 (21-22) caudal. The lateral-line system is hypertrophied and their is an elaborated system of superficial neuromasts arranged in distinct ridges on the head and along the body. Caudal sensory papillae are also found on the caudal fin. Scales are small, imbedded, and cycloid. The urogenital pore and anus are jugular in position. Recent molecular work indicates that S. poulsoni is most closely related to the Southern Cavefish (Typhlichthys subterraneus).

Lateral view of an Alabama Cavefish.

Distribution:Speoplatyrhinus poulsoni is known from just a single cave system, Key Cave, in Lauderdale Co., Alabama, within the Tennessee River watershed. Despite numerous surveys for cavefishes in other caves in close proximity to Key Cave along the Tennessee River and elsewhere, no additional populations of S. poulsoni have been found in northwestern Alabama.Habitat: Key Cave is a maze-like cave system developed in the Mississippian-aged Tuscumbia Limestone. The aquatic habitat in Key Cave consists of a series of pools with little flow that occur in a zone of seasonal oscillation of the local water table. Several of these pools are quite deep reaching depths of up to 5 m depending on seasonal water levels. Significant bat roosts occur near at least two pools where guano occasionally slides or falls into the water.

Close-up dorsal view of head.

Natural History: Little is known regarding many aspects of the life history and ecology of S. poulsoni because of its rarity. Some
authors have speculated that females may incubate eggs and protect
young fry within the branchial chamber, based on the jugular position of
the vent. This behavior has been observed in some populations of the
related Northern Cavefish (Amblyopsis spelaea) but has yet to be demonstrated for any other amblyopsid, including S. poulsoni.
Individuals as small as 12-15 mm SL have been observed in February and
November, suggesting that S. poulsoni may breed in the summer months. In
addition, the female holotype contained developing ova and was
collected in late May, also supporting a summer spawning season. The diet of S. poulsoni has not been studied but likely includes copepods, isopods, amphipods, and perhaps small crayfish. An undescribed species of cave shrimp was recently found in Key Cave and likely is prey for S. poulsoni. Predators are unknown and its thought that S. poulsoni is one of the top consumers in the Key Cave ecosystem. Sympatry of cavefish species is rare; however, S. poulsoni cooccurs with T. subterraneus within Key Cave. Typhlichthys subterraneus is common in caves throughout central Kentucky, central Tennessee, northern Alabama, and extreme northwestern Georgia. The absence of S. poulsoni but presence of T. subterraneus from nearby cave systems suggest that competitive interactions might influence the distribution of S. poulsoni. However, this hypothesis has not been examined.

Dorsal view of an Alabama Cavefish.

Conservation:Speoplatyrhinus poulsoni is one of the rarest vertebrates in North America. The
population in Key Cave is small and no more than 10
individuals have ever been observed during a single survey.The U.S. Fish and Wildlife Service listed S. poulsoni as threatened in 1977 based on its restricted distribution, low abundance and potential threats to this species, including disturbance of a maternity colony of endangered Gray Bats (Myotis grisescens) whose guano is an important source of nutrients and energy for the aquatic ecosystem in Key Cave and groundwater pollution from pesticides as well as a proposed industrial park for the city of Florence. The threat status was later reclassified as endangered in 1988, as a sewage sludge disposal operation was found to occur within the recharge area of Key Cave. In addition, herbicide and pesticide runoff from cotton fields was found to have direct access into Key Cave via surface seeps. Loss of aquatic habitat from lowering of local groundwater levels by increased pumping also has been cited as a concern. The U.S. Fish and Wildlife Service purchased several hundred acres of land within the recharge zone of the cave and established the Key Cave National Wildlife Refuge. The agricultural land within the refuge is still maintained but cotton was replaced with corn and soybeans. In addition, all chemical use was restricted. This agricultural land is slowly being converted to upland forest and native grasslands. The most recent surveys for S. poulsoni indicate that the population is stable and recruitment is still occurring.Fun Fact:Speoplatyrhinus poulsoni is named in honor of Dr. Tom Poulson, a prominent cave biologist who has studied amblyopsid cavefishes and other cave life since the late 1950s.Select References

Tuesday, February 12, 2013

Ginny Adams and colleagues describe a new troglomorphic species of sculpin (family Cottidae) endemic to just five cave systems of the Central Perryville and Mystery-Rimstone karst in Perry County, Missouri in a recent article in Zootaxa (Adams et al. 2013). This new species, the Grotto Sculpin (Cottus specus Adams and Burr), was previously recognized as several unique troglomorphic populations of the widespread Banded Sculpin (C. carolinae) (Burr et al. 2001). Currently, C. specus is only known from cave systems and their spring resurgences in tributaries of the Bois Brule River drainage, including Cinque Hommes Creek and Blue Spring. The type-locality is Mystery Cave in Perry County, Missouri.The Grotto Sculpin can be distinguished from other members of the genus Cottus, including the closely-related C. carolinae, by reduced eyes (typically 1-5% of standard length versus 5-9% standard length) and an increase in cephalic lateralis pore size. The overall eye volume, lens and dermal cornea of the eye are also reduced in C. specus compared to C. carolinae. Pigmentation is highly variable with some individuals of C. specus lacking all apparent pigmentation in the fins and on the body, while others possess the general banding pattern of dorsal saddles typically found in C. carolinae. Cottus specus is also distinct genetically from C. carolinae based on analyses of the mitochondrial control region.Cottus specus is a species of high conservation concern. The known distribution of this cavefish is comprised of just five populations that are threatened by groundwater pollution in the form of bioaccumulative organic contaminants. Two of the five populations have experienced mass mortalities of unknown origin in the past 15 years. In addition, C. specus is generally found at much lower densities than C. carolinae, which may limit the ability of populations to recover from acute anthropogenic disturbances. Consequently, Adams et al. advocate the formal protection of C. specus at both the state state and federal level.Although not directly discussed in the paper, C. specus likely represents a cave form that has only recently colonized subterranean waters based on less elaborate troglomorphic features compared to other cavefish species in North America and levels of molecular sequence divergence between C. specus and other nearby C. carolinae populations. My interpretation is that C. specus likely colonized caves only recently sometime within the last million years, perhaps caused by or associated with climatic fluctuations during the Pleistocene.The cave and karst regions of Missouri are now home to three species of cavefishes, including Cottus specus. The other two species are the federally threatened Ozark Cavefish (Troglichthys rosae) and the Salem Plateau Cavefish (Typhlichthys eigenmanni). Typhlichthys eigenmanni was recently resurrected from T. subterraneus by Niemiller et al. (2012). Troglomorphic populations of sculpins (Cottus sp.) have been reported from Pennsylvania and West Virginia as well (Williams & Howell 1979; Espinasa & Jeffery 2003).ReferencesAdams GL, Burr BM, Day JL, Starkey DE (2013) Cottus specus, a new troglomorphic species of sculpin (Cottidae) from southeastern Missouri. Zootaxa 3609: 484-494.Burr BM, Adams GL, Krejca JK, Paul RJ, Warren Jr ML (2001) Troglomorphic sculpins of the Cottus carolinae species group in Perry County, Missouri: distribution, external morphology, and conservation status. Environmental Biology of Fishes 62: 279-296.Espinasa L, Jeffery WR (2003) A troglomorphic sculpin (Pisces: Cottidae) population: geography, morphology and conservation status. Journal of Cave and Karst Studies 65: 93-100.Niemiller ML, Near TJ, Fitzpatrick BM (2012) Delimiting species using multilocus data: diagnosing cryptic diversity in the southern cavefish Typhlichthys subterraneus (Teleostei: Amblyopsidae). Evolution 66: 846-866.Williams JD, Howell WM (1979) An albino sculpin from a cave in the New River drainage of West Virginia (Pisces: Cottidae). Brimleyana 1: 141-146.

Wednesday, January 23, 2013

This is my first attempt at publishing a video of subterranean life on my YouTube channel. The video was shot using an Olympus TG-1iHS 12 MP Waterproof Digital Camera under low-light conditions. The quality isn't great but itis not terrible either. I will work toward producing higher quality videos in the future.

The video features a cave dipluran crawling along a rock boulder in the dark zone of Hering Cave, Madison Co., Alabama. Diplurans are primitive wingless relatives of insects belonging to the class Hexapoda. They have three pairs of walking legs along with two long antennae extending from the head and two long cerci extending from the posterior end of the abdomen. Diplurans use their antennae and cerci in concert to sense their environment. In addition to lacking wings, diplurans also lack eyes.

Diplurans are common in caves throughout the Interior Plateau, Appalachians and Ozark Highlands of eastern North America where they are most often observed on damp substrates near a water source, such as along mud banks of cave streams. The species in the video is Valentine's Cave Dipluran (Litocampa valentinei), which occurs in caves of northeastern Alabama and south-central Tennessee along the Cumberland Plateau.

Description:Gyrinophilus palleucus is one of the four species of cave-obligate salamanders found east of the Mississippi River in the United States. They are large, aquatic salamanders that can reach lengths of 210 mm. Unlike most species of salamanders, Gyrinophilus palleucus does not readily undergo metamorphosis and attains sexual maturity in the larval stage. Consequently, they retain the conspicuous paired gills located on each side of the back of the head throughout life. Adults have a broad head with a flattened, shovel-like snout. They eyes are reduced in size compared to related surface-dwelling cousins like the Spring Salamander (G. porphyriticus) and Red Salamander (Pseudotriton ruber), but they are not completely degenerate as observed in other obligate cave-dwelling salamanders. However, some adults may have skin that completely covers their eyes. Also unlike other cave salamanders, G. palleucus is distinctly pigmented and ranges in color from pale pink and lacking spotting to dark reddish purple or brown with distinct spots or blotches on the back. Adults also have a series of unpigmented dots that represent pores of the lateral line system on the head and along the sides of the body that are used to detect moving prey, conspecifics and potential predators in their aquatic environment. Juveniles generally resemble adults but are much paler, lack conspicuous spots or blotches, and possess eyes that are proportionally larger relative to head size. Two subspecies are recognized: the Pale Salamander (G. p. palleucus) and the Big Mouth Cave Salamander (G. p. necturoides). These subspecies differ in coloration, relative eye size and number of trunk vertebrae but are thought to hybridize throughout much of northern Alabama.

Juvenile, Jackson Co., Alabama

Distribution:Gyrinophilus palleucus has been reported from 80 localities in northern Alabama (39 caves), northwestern Georgia (2 caves) and central Tennessee (38 caves and 1 spring). Its distribution includes caves in the Inner Nashville Basin, Eastern Highland Rim and escarpments of the Cumberland Plateau.Habitat: Both adults and juveniles are most often observed resting on the bottom of shallow pools in the dark zone of subterranean streams but are also can be found in riffles and rimstone pools. They are most often found underneath rocks or within mats of organic debris washed into caves. Gyrinophilus palleucus has been found within the twilight zone of caves on occasion and at least one report was from a surface spring after heavy rainfall.

Adult, Coffee Co., Tennessee (Photo by Matthew L. Niemiller)

Natural History: Little is known about the life history and ecology of G. palleucus. This is particularly true for aspects of reproductive biology. Eggs have never been found, although it is presumed that mating and egg-laying occurs from autumn to early winter. Although data are limited, it appears that G. palleucus is long-lived and may take 5-8 years to reach sexual maturity. Tennessee Cave Salamanders are one of the top predators in the cave systems they inhabit. They will eat almost anything that will fit into their mouths, including isopods, amphipods, worms, small crayfish, and even smaller conspecifics. Metamorphosis is rare in the wild, but G. palleucus can be induced to metamorphose in the lab.

Adult, Warren Co., Tennessee (Photo by Matthew L. Niemiller)

Conservation: Populations of G. palleucus face a number of threats, such as habitat degradation, groundwater pollution, and alteration of water flow and organic input into cave systems associated with urbanization, mining, silviculture, agriculture, and the construction of dams. However, it is unclear what negative impacts these threats have had on populations of G. palleucus. Several populations studied appear to be stable and are under no immediate threat of extirpation. Moreover, recent surveys have revealed that the species is more widespread and abundant than previously believed. The entrances to several cave systems inhabited by G. palleucus are owned or managed by state or federal agencies or cave conservation organizations, which affords some protection.

Thursday, January 3, 2013

The Biology Section of the National Speleological Society recently published Cave Life of the Virginias: A Field Guide to Commonly Encountered Species in June 2012 written by Drs. Daniel W. Fong, Megan L. Porter, and Michael E. Slay. To my knowledge, this work represents the first field guide on subterranean life of eastern North America that can actually be taken underground and can hold up to the wear and tear of caving. The 42 spiral-bound pages are laminated and the book is perfectly sized to fit into a cave pack.Cave Life of the Virginias highlights species that are commonly observed in Appalachian caves of Virginia and West Virginia to help cavers identify these unique animals. The beginning of the book briefly discusses caves as important habitats for many species, cave zones inhabited by wildlife, and the ecological classification of cave organisms. The twenty species accounts are organized into three groups based on where particular are most frequently encountered: the entrance zone, transition zone, and dark zone. Each species or species complex (e.g., cave millipedes) is illustrated with a photograph and often with a silhouette image (for species that are small) representing the actual size of the organism. For species or species complexes that occur in the dark zone, distribution maps are provided. Species accounts provide detailed information on the appearance, coloration, and other distinguishing features to assist in identification. Additional information on natural history and conservation is also provided. The final five pages of the book are devoted to avenues to seek additional information about the species highlighted, including books, journal articles, and websites.Cave Life of the Virginias is written for a general audience with some knowledge of biology (i.e., the average caver). Perhaps its best feature are the high quality photographs taken by several cave biologists that begin each species account, including some species that are quite small (<5 mm). While this book won't allow you to identify most cave organisms to species (which often requires dissection for many groups), Cave Life of the Virginias can be used to quickly determine a springtail from a dipluran or an isopod from an amphipod.

I highly recommend that anyone with even a slight interest in caving and cave life purchase Cave Life of the Virginias. The book is very affordable at $16 US and can be purchased from the NSS Bookstore or from Speleobooks. Proceeds generated from sales are used toward the publication of additional field guides in the series.Funding for Cave Life of the Virginias was provided by the Cave Conservancy of the Virginias (administered by Karst Waters Institute). Cave Life of the Virginias is the first of a series of cave life field guides of the United States. Future titles will highlight subterranean biodiversity of TAG and the Ozarks.

About Me

I am an evolutionary ecologist and cave biologist who studies the evolutionary biology, ecology and conservation of subterranean organisms. I have a B.S. and M.S. from Middle Tennessee State University and a Ph.D. from the University of Tennessee. Since 2011, I have been a Gaylord Donnelley Environmental Fellow at Yale University. When not studying cave life, I enjoy spending time with my girlfriend Denise, fantasy football, and watching Indiana Hoosiers basketball.